Ceramic manufactures

ABSTRACT

Prosthetic implant or component therefor of a magnesium oxide stabilized transformation toughened zirconia (Mg-TTZ) ceramic can be made by providing a bisqued initial green body by compressing powder through a cold isostatic press and heating to a bisque stage. Then, without embedding it in an embedding mass, the bisque is machined to have a shape of the same proportions as the shape of, but larger than, the ceramic portion of a fired prosthetic implant or component product. Firing can provide the fired Mg-TTZ ceramic body product.

CROSS-REFERENCE CLAIMS OF PRIORITY

This claims the benefits as a divisional of U.S. regular utility patentapplication Ser. No. 11/220,997 filed on Sep. 7, 2005 A.D., which claimspriority benefits of U.S. provisional patent application No. 60/677,240filed on May 3, 2005 A.D. and is a continuation-in-part of InternationalPatent Application No. PCT/US2004/006908 filed on Mar. 5, 2004 A.D.,which, as does the '997 application and the present matter, claimspriority benefits of U.S. provisional patent application Nos. 60/452,704filed on Mar. 7, 2003 A.D., and 60/463,922 filed on Apr. 18, 2003 A.D.The same is claimed under 35 USC 119, 120, 363 and/or 365. Thespecifications of the above mentioned '997, '240, '908, '704 and '922applications are incorporated herein by reference in their entireties,which, of course, includes their drawings.

FIELD AND PURVIEW OF THE INVENTION

This invention concerns a method of manufacture of a ceramic body aswell as the ceramic body itself. In a particular field, the ceramic bodyembraces a bodily implant, especially a load-bearing joint implant. Forexample, the implant may be a femoral knee component in its primary orrevisional form, which can be a ceramic posterior stabilized femoralcomponent for a knee implant, and, in another exemplary embodiment, canbe an artificial knee implant component made to include ceramic having arotation device for restraining a femoral component in relation to acorresponding tibial component that can have natural load transfer.Additional ceramic manufactures can be provided.

BACKGROUND TO THE INVENTION

The quest for stronger, more versatile ceramic products is an ongoing,very important concern. Difficulties exist, for instance, in providingsufficiently strong, finished ceramic bodies that would conform toprecise and intricate geometries. In light of this, many ceramicproducts, which would be highly desirable, remain unavailable.

For example, although an alumina femoral knee component is known fromJapan, it is made in a manner only to address the most basic of femoralimplant designs, and problems with it include its great expense, as itmay be made by machining a fired block. Attempts to provide ceramicadvanced femoral knee components apparently have met with failure, andsuch more intricate ceramic implants that require great strength arelacking in the art. As an example of such an implant is a posteriorstabilized femoral component for a knee implant. In fact, experts in theart are skeptical that such can be made. Note, too, Amino et al., U.S.Pat. No. 5,549,684.

It would be desirable to overcome such difficulties. It would bedesirable, moreover, to provide an efficient and cost effective methodto do the same.

In a particularly notable implant provision, Goodman et al., U.S. Pat.No. 5,766,257, discloses an artificial joint having natural loadtransfer. In a particular embodiment, the joint is a knee. Although itis disclosed that a ceramic substance may be employed, preferably thejoint is of metal construction. For example, its femoral component frameis a cast or forged cobalt-chromium alloy, and its tibial componentframe is a titanium alloy, with a Co—Cr alloy rotation device andbearings of ultra high molecular weight polyethylene (UHMWPE). See also,Zimmer, Inc., NexGen (Reg. U.S. Pat. & Tm. Off.) System Rotating HingeKnee Design Rationale, 2002.

Additional modularity may be provided in such a knee implant. See,Serafin, Jr., U.S. Pat. No. 6,629,999.

Employment of ceramic in bodily implants, to include a posteriorstabilized femoral component and the knee implants of the '257 and '999patents as well as other implants could be of benefit. For example,certain patients are allergic to slight amounts of Nickel found in Co—Cralloys, and ceramic may provide for a hard articulating surface.However, for such complex knee implant components as noted above inparticular, a more practical application of the basic concept ofemploying ceramics is needed.

Serafin, Jr., et al., in WO 2004/080340, the publication of thementioned '908 application, disclose ceramic manufactures. Therein, aceramic body can be made by providing an initial green body of ceramic,machining it, and firing it.

Other ceramic making art is known. For example, Bodenmiller et al., inU.S. Pat. No. 6,495,073, disclose a method for the manufacture ofmedical, dental-medical, dental-technical and technical parts fromceramics. Therein, a powdery raw ceramic is compressed to form a ceramicgreen compact, and the compact is embedded in an embedding mass, forexample, a wax, and machined in the embedding mass. After machining, thepart is de-waxed, and fired. Among drawbacks to such methodology,however, is that embedding mass wax can gum up or clog machining tools.

It would be desirable to avoid embedding mass wax in ceramic work, ingeneral, and, in various cases, avoid or limit wax use.

GENERALIZED SUMMARY OF THE INVENTION

In general, the present invention provides, in one aspect, a method formaking a ceramic body, which comprises providing an initial green bodyof ceramic; and machining the initial green body to provide a machinedgreen ceramic body. In the method, in one embodiment, machining theinitial green body can be carried out without embedding the initialgreen body in an embedding mass; in another embodiment, bisquing theinitial green body can form a bisqued green body of ceramic, which canbe infiltrated with an adjuvant, removed from any gross externaladjuvant by which the bisqued green body was contacted for theinfiltration, and machined as a removed, infiltrated, bisqued greenbody. For one instance, the machining may be conducted with the aid of adevice that does not provide contact of the initial green body with anattachable substance, for example, machining wax. In such a case, andwith the alternative, detailed and even highly detailed ceramic productscan be generated without embedding in an embedding mass, and so,avoiding drawbacks associated with the same. The machined green ceramicbody may be fired and/or further processed to provide a more finishedceramic body.

Other aspects are the machined green ceramic and more finished ceramicbodies, which may be prepared by the noted method and/or made ofcertain, particular ceramics. For various illustrations of the manypossible, the ceramic body can be a femoral component for a posteriorstabilized knee implant, a dental implant or bridge, an ice skatingblade, and so forth, which can include a component body for anartificial rotation device containing knee implant prosthesis having acomponent frame, wherein the rotation device includes a swingable,depending male-type part; the knee prosthesis has a femoral componentwith condylar articular surfaces, plus the rotation device, and has atibial component with meniscal articular surfaces that mate with thecondylar articular surfaces of the femoral component, plus a rotationdevice receptacle that includes a female-type part, so that the femoralcomponent is matable to the tibial component through male-femalecooperation of the rotation device and the rotation device receptacle,and the knee prosthesis generally has natural load transfer capabilityby anatomical gliding contact of the condylar and meniscal articularsurfaces against one another during anatomical rotation in addition toanatomical flexion and extension.

The invention is useful in providing ceramic items.

Significantly, by the invention, the art of ceramics manufacture isadvanced in kind by a unique and highly efficient method. Attachablesubstances such as machining wax, which often must be removed in laterprocessing steps, can be avoided, and so can embedding be avoided. Many,many types of ceramic bodies can be produced, to include intricatemedical and dental implants, and the costs of making these are reduced.Moreover, bothersome or contaminating substances are absent from themachining. In a particularly advantageous embodiment, a vacuum chuck isemployed. Thus, strong, finished ceramic bodies which conform to preciseand intricate geometries are now available. For further example, aceramic posterior stabilized femoral knee component with great strength,heretofore unknown to those skilled in the art, is provided. Provisionis made for other ceramic bodily implants or implant components, bothcomplex and simple, including other types of femoral knee implantcomponents, single- and multi-piece unicompartmental joint aligningdevices, ankle joint condyle-containing components, femoral head balls,humeral shoulder hemispheres, and so forth. Thus, a more practicalapplication of the basic concept of employing ceramics in compleximplants such as the knee as generally noted above is provided. In aparticular aspect, strong, finished components in rotating devicecontaining knees, which conform to precise, intricate geometries, aremade available, and component bodies for an artificial rotation devicecontaining knee prostheses made of zirconia ceramics are herebyadvantageously provided, for femoral and/or tibial components. Othertypes of ceramic bodies are made available such as gears, flow-controlfittings, and so forth. Certain zirconia ceramic bodies are mostadvantageously provided.

Numerous further advantages attend the invention.

DEPICTION OF SEVERAL EMBODIMENTS OF THE INVENTION

The drawings form part of the specification hereof. With respect to thedrawings, which are not necessarily drawn to scale, the following isbriefly noted:

FIG. 1 shows a graph illustrating general phases of zirconia ceramics.

FIG. 2 shows a scheme of manufacture with the invention.

FIG. 3 shows top view of a finished ceramic body of the invention,embodied as a posterior stabilized femoral knee implant component.

FIG. 4 shows a medial to lateral side view of the component of FIG. 3.

FIG. 5 shows a front view of the component of FIG. 3.

FIG. 6 shows a rear view of the component of FIG. 3.

FIG. 7 is a sectional view of the component of FIG. 3, taken along 7S-7Sof FIG. 3.

FIG. 8 is a rear, top perspective view of the component of FIG. 3.

FIGS. 9-15 show some other finished ceramic bodies hereof, embodied asfollows:

FIG. 9. A modular ceramic knee implant with a metal intramedular femoralpost and metal securing washer, with a metal screw fastener, also with ametal or ceramic peg for a posterior stabilizing stop, shown from oneside in partial section.

FIGS. 10-11. A one-piece unicompartmental knee joint spacer as a planview (FIG. 10) and side view (FIG. 11).

FIGS. 12-14. A two-piece unicompartmental knee joint aligning device,shown as a side sectional view (FIG. 12); a side sectional view (FIG.13) taken perpendicularly to the view of FIG. 12, and a top view (FIG.14) in a sliding engagement mode.

FIG. 15. A temporal mandibular joint implant cap.

FIGS. 16-19 show other finished ceramic bodies, embodied as industrialapparatus, components, or devices, as follows:

FIG. 16. An industrial bearing, shown in perspective.

FIG. 17. Flow control apparatus, shown in plan.

FIG. 18. A set of gears, shown in elevation.

FIG. 19. A set of pulleys, shown in elevation.

FIG. 20 shows a scheme of manufacture with the invention to make anotherceramic body, here a finished base component for an artificialprosthetic knee joint implant, which will contain a rotation device.Compare, FIG. 2.

FIG. 21 is a front (anterior to posterior direction) of an artificial,prosthetic knee joint implant that may have at least a ceramic componentbody among its femoral and tibial components such as the base femoralcomponent body shown in FIG. 20, which contains a rotation device.

FIG. 22 is an exploded view of the joint of FIG. 21.

FIG. 23 is a left side view (lateral to medial direction) of the femoralcomponent to the joint of FIGS. 21 and 22.

FIG. 24 is a rear view (posterior to anterior direction) of the femoralcomponent of FIG. 23.

FIG. 25 is a left side view of the rotation device member of the femoralcomponent in FIGS. 22-24.

FIG. 26 is a side view of the rotation device femoral-tibial taper pinof the joint as seen in FIG. 22.

FIG. 27 is an exploded, perspective view of a femoral component ofanother artificial, prosthetic knee joint of the invention containing arotation device and having a ceramic body.

FIG. 28 is an exploded, side view of the prosthetic knee joint havingthe femoral component of FIG. 27.

FIG. 29 is a front, perspective view of the joint of FIG. 28, assembledand having several augments to accommodate bone loss in place in itsfemoral component.

FIG. 30 shows perspective and side views illustrating various femoralaugments, some of which can be seen within FIG. 29.

FIG. 31 is a side view of the tibial base plate found within the jointof FIG. 28.

FIG. 32 is a top, perspective view of the tibial base plate of FIG. 31.

FIG. 33 is a perspective view of some partial tibial augments that maybe employed with the tibial base plate of FIG. 31.

FIG. 34 is a perspective view of a ceramic provisional femoral componenthaving a modular rotation device employed for fitting the patient to afemoral component such as that of FIG. 27 with a properly sized rotationdevice.

FIG. 35 is a perspective view of a ceramic provisional femoral componenthaving snap-in augments employed for fitting the patient to a femoralcomponent such as that of FIG. 27 with augments as may be necessary tomake up for a lack of bone. The augment provisional components snap intothe femoral provisional component.

FIGS. 36-37 show side views of a ceramic femoral provisional cuttingguide for implantation of a femoral component such as that of FIG. 27with drilling, as follows:

FIG. 36. In a proximal direction into resected femur.

FIG. 37. In a posterior direction into resected femur.

FIG. 38 is a saggital sectional view of a modular ceramic human kneejoint of the invention.

FIG. 39 is a rear, section view of the joint of FIG. 38.

FIG. 40 is an exploded, rear sectional view of a modular ceramic kneejoint of the invention, similar to that of FIGS. 38 and 39, employingpin type attaching of its axial (taper) pin.

FIG. 41-43 show exploded, saggital sectional views of ceramic femoralknee components with modularity, as follows:

FIG. 41. Module-in-module.

FIG. 42. Top-insert stem.

FIG. 43. One-piece box with stem, plus a rotation device added thereto.

FIG. 44 is a rear sectional view of the femoral component frame of FIGS.41-43.

FIG. 45 is a saggital sectional view of the insertable rotation devicewith a swingable, depending male type part of the modular joint of FIGS.38 and 40.

FIG. 46 is a rear sectional view of the insertable rotation device ofFIG. 45.

FIG. 47 is an exploded side view of another embodiment of a modularceramic tibial tray of the invention.

FIG. 48 is an exploded rear view of the tray of FIG. 47.

FIG. 49 is an exploded rear view of another embodiment of a modularceramic tibial tray of the invention.

FIGS. 50-51 show views of a zirconia ceramic cruciate-retaining femoralcomponent implant for a left human knee implant, as follows:

FIG. 50. Left, front, perspective plan view.

FIG. 51. Bottom view.

FIG. 52 is a rear, perspective view of a ceramic, unicompartmentalfemoral component condylar implant.

FIGS. 53-54 show views of a ceramic patellofemoral joint implant for aleft human knee, as follows:

FIG. 53. Top, rear perspective.

FIG. 54. Front perspective.

FIGS. 55-58 show views of inter-spinal vertabra ensembles forimplantation in adjacent, facing vertebral bodies for replacement of adisc, embodied as follows:

FIGS. 55-56. Cap or cup mounting style, shown as a side, exploded view,with one component in section (FIG. 55); and a top view taken alongarrow 41A (FIG. 56).

FIGS. 57-58. Peg or post mounting style, shown as a side, exploded view,with one component in section (FIG. 57); and a top view taken alongarrow 42A (FIG. 58).

FIGS. 59-64 show views of an ankle implant ensemble, with FIGS. 59-62 atalus cap, which may be a hemi-implant, shown in top (FIG. 59); bottom(FIG. 60); side (FIG. 61); and front (FIG. 62) views; and with FIGS.63-64 a tibial tray, shown in side (FIG. 63) and front (FIG. 64) views.

FIG. 65 shows in more detail machining of an initial green body ofceramic that is held with a vacuum and/or manual chuck, said bodyembracing teeth.

FIG. 66 shows a ceramic ice skate blade makable hereby.

FIGS. 67-69 show views of a ceramic intermediary articulation plate fora tibial tray and liner, with FIG. 67 showing the plate; FIG. 68 a topview of the plate mounted in the tray; and FIG. 69 a sectional view ofthe assembled plate, tray and liner, taken along 69-69 in FIG. 68.

DETAIL FURTHER ILLUSTRATING THE INVENTION

The invention can be further understood by additional detail, especiallyto include that which is set forth below, which may be read in view ofthe drawings. Such is to be taken in an illustrative and not necessarilylimiting sense.

In general, in accordance with the practice of the present invention, aceramic body can be made by providing an initial green body of ceramic,and machining the initial green body to provide a machined green ceramicbody. The machined green ceramic body may be fired and/or furtherprocessed to provide a more finished ceramic body.

In certain embodiments of the present invention, one or more parts toone or more components of the knee joint implant is made of ceramic.Preferably, at least the basic femoral component with its condylararticulating surfaces is made of ceramic. Typically the ceramic condylararticulating surfaces articulate with a corresponding tibial tray linermade of ultra high molecular weight polyethylene (UHMWPE). Other partsof the femoral and tibial components may be made of, or to include,ceramic.

In certain other embodiments hereof, various additional articles ofmanufacture may be made. These include ceramic.

The ceramic may be any suitable type. Among these may be mentionedceramics from “A” to “Z,” to include alumina to zirconia, and mixturesthereof. A representative ceramic may be a boride, carbide, nitride,oxide, silicate and so forth of Al, Si, Sc, Y, La, the lanthanide serieselements, Ac, the actinide series elements, Ti, Zr, Hf, V, Nb and/or Taand so forth and the like. A ceramic may be toughened; thus, forexample, an alumina may be a toughened alumina as known in the art.Preferably, the ceramic is a zirconia ceramic. The ceramic may bestabilized, and any suitable stabilizer may be present in any suitableamount. For example, the zirconia ceramic may generally be a partiallystabilized zirconia (PSZ) which is a zirconia ceramic stabilized, forexample, with about three to three and one half percent by weightmagnesium oxide, or with about from four to five percent by weightyttrium oxide, and which exists in a phase that may in essence span orbe selected from tetragonal and/or cubic phases; and, from among the PSZceramics, a magnesium oxide stabilized transformation toughened zirconia(Mg-TTZ), which is a zirconia ceramic stabilized with approximatelythree to three and one half percent by weight magnesium oxide and whichexists to a substantial extent in a tetragonal phase; or a yttrium oxidetetragonal zirconia polycrystalline (Y-TZP), which is a zirconia ceramicstabilized with approximately three mole percent yttrium oxide andexisting to include in a tetragonal phase. Compare, FIG. 1.

The finished ceramic may contain other substances. For example, zirconiaceramics typically contain a small amount of hafnia ceramic substances,say, about two percent by weight, owing to the fact that Hf is foundwith Zr in nature and is difficult to remove from Zr. This, however,need not be, and frequently is not, detrimental.

Beneficially, the ceramic is the Mg-TTZ, especially for prostheticimplants, and those which are load bearing and/or are joint replacementparts or components, the ceramic is the Mg-TTZ, to include for reasonsof its good hardness and toughness, and its excellent resistance toheat- and/or water-induced reversion toward a monoclinic phase. Forexample, a general comparison of alumina, Y-TZP and Mg-TTZ can be madeas follows:

Strength after firing: Y-TZP>Mg-TTZ>alumina.

Strength after autoclaving: Mg-TTZ>alumina>Y-TZP.

Assigning arbitrary strength numbers to these ceramics for purposes offurther illustration may yield the following values:

After firing: Y-TZP (150); Mg-TTZ (125); alumina (100).

Post-autoclave: Mg-TTZ (125); alumina (95); Y-TZP (50).

Thus, it may be said that Mg-TTZ does not revert to a monoclinic phasethrough the in vitro action of hot water, or it is not degraded orattacked by water. With in vivo use, the following has been generallyobserved with respect to wear for alumina and Y-TZP implanted femoralhip balls:

At 1-4 years retrieval: Y-TZP better than alumina.

At 5-8 years retrieval: Y-TZP and alumina nearly same.

At 9-10, or more years: Alumina better than Y-TZP.

Accordingly, in vivo, Mg-TTZ, known, for example, to have been implantedas femoral hip balls (with bores drilled after firing), should beobserved to provide better short and/or long term wear than alumina andbetter long term wear than Y-TZP.

Desirably, the ceramic body initially is made from a micropowder and/ornanopowder. For instance, a zirconia ceramic may be made from monocliniczirconia powder with an about from 0.5-micron (um) to 10-umcross-section, as a micropowder, or with an about from 1-nanometer (nm)to 500-nm cross-section, as a nanopowder, which micropowder ornanopowder may contain about from two to five percent by weightmagnesium oxide as a stabilizer. Preferably, the zirconia powder has anabout from 1-um to 2-um cross-section, as the micropowder, or an aboutfrom 15-nm to 450-nm cross-section, as the nanopowder, and containsabout from 3.1 to 3.4 percent by weight magnesium oxide.

The initial green body of ceramic can be provided by any suitable methodor process. Pressure molding is preferred to make the initial greenbody, especially by a cold isostatic press (CIP) technique. Thus, apowdered ceramic material is fed into a cavity of a high-pressure press,and formed under pressure into the initial green body. A binder may beemployed if needed or desired. Typically, a binder is employed with theceramic powder if it is a micropowder or larger size. It may be the casethat a binder is not required for the initial green body of nanopowder.

The initial green body of ceramic is made to have a suitable density.Generally, the density of the initial green body is at least abouttwenty percent of the theoretical density for that ceramic. Preferably,the density of the initial green body is at least about thirty percentof theoretical, and more preferably at least about fifty percent oftheoretical. Some may consider that higher theoretical densities of theinitial green bodies may be provided by the employment of the smallerpowders, others not, which may depend on the material. (Nanopowders,however, may sinter better than larger powders.) Higher theoreticaldensities may be provided by higher pressure, and so forth.

The initial green body may be provided in any suitable shape. Convenientshapes can include cylinders, tetrahedra, triangular prisms, rectangularor cubic blocks, regular pentagonal prisms, and so forth.Advantageously, the initial green body of ceramic is provided as arectangular or cubic block.

For machining, certain initial green bodies may be left raw and pressed,and others may require heating to provide a bisque, which is consideredto be a form of an initial green body. Thus, certain ceramic powderssuch as a zirconia nanopowder may be machined in a raw, pressed state.Certain other ceramic powders such as a micropowder for conversion intoMg-TTZ are bisqued. The heating required to form a bisque generally isconsidered mild. For example, a zirconia micropowder may be bisqued attemperatures about from one hundred to one thousand or eleven hundred ormore degrees C., for about from one to ten hours.

In the practice of the invention, the initial green body is machined toprovide the machined green ceramic body. Machining can be by anysuitable method, to include by hand, by lathe, by drilling, cutting, andso forth, but preferably is carried out with a multi-axis precisioncutting or tooling machine, for example, a computerized numericalcontrol (CNC) machine. Generally, temperatures during the machining canbe ambient temperatures. The machined green ceramic body may have anysuitable shape, but preferably has a shape which is a precursor shape,analogous in most essential aspects, to the shape of any finishedceramic body. In light of this, the present method has a significantadvantage that the machined green body may be provided with a complexshape so that if a finished ceramic would be made from it, minimaltransformation to the essential shape of the body occurs. Thus, suchasymmetrical, complex geometries as those of femoral components for aknee, to particularly include revisional femoral knee implantcomponents, are readily gained. Other complex geometries, asillustrations of the versatility of the invention, in the field ofsurgical implants may include knee joint implant tibial components,unicompartmental knee joint aligning devices of one or more pieces,ankle joint implant components, spinal components, temporal mandibularjoint implants, and so forth. Of course, other bodies can be made as themachined green body, including surgical implants such as hip femoralheads, shoulder humeral hemispheres, and so forth, which canadvantageously include any trunnion receiving bores provided inprecursor form so that the machined green body has less symmetry than anuninterrupted ball or generally planarly truncated ball (uninterruptedhemisphere), i.e., symmetry of a C-infinity point group, to include hipfemoral and shoulder humeral heads with trunnion-receiving, tapered,truncated frustoconical bores, or a shape more asymmetric thanC-infinity. And so, for additional examples, complex geometries of thefemoral component and/or its rotation device and/or an insertable spike,and the tibial component tray and/or an insertable spike are readilygained.

The machined green ceramic body, as a precursor to a finished ceramicbody, is provided suitably larger than the finished ceramic body. Thus,typically depending on the density of the machined green ceramic bodyand the density of the finished ceramic body, the machined green ceramicbody may be about from one half to eighty percent larger than thecorresponding finished ceramic body, in many cases about from ten tothirty percent larger. With the zirconia ceramics and Mg-TTZ inparticular, typical undersizes of the more finished ceramic in relationto the machined green body made from micropowder run about from fifteento twenty-five percent, to include about from sixteen to twenty-threepercent, less than the size of the finished ceramic body. In otherwords, an eighteen percent undersized more finished ceramic based on thecontrolling size of the machined green body may be considered to beequivalent to an about one hundred twenty-two percent oversized machinedgreen body in relation to the controlling size of the more finishedceramic body. Thus, the relationship (I) generally obtains:Oversize %=(100%/(100%−undersize %))(100%).  I.For example, a more finished ceramic body which is twenty percentundersized from a machined green body, is made from the machined greenbody which is 1.25 times as large (125%) as the more finished ceramicbody.

Preferably, the more finished ceramic body is provided. This can beaccomplished through at least one heating step.

The more finished ceramic body can be provided through firing of themachined green body. The firing may be conducted at any suitabletemperature, for instance, within ranges about from one thousand tothree thousand degrees C., for any suitable time. A temperature gradientleading to the firing temperature in the ceramic body is preferred, toinclude as may be conducted within ranges of about from one half totwenty degrees per minute. Annealing of the fired piece may immediatelyfollow the firing, which may be carried out at any suitable temperature,for instance, within ranges about from seven hundred to one thousandeight hundred degrees C., for any suitable time. Further ceramicprocessing can include hot isostatic press (HIP) action, as may bedesired or pertinent to certain ceramics. The fundamentals and practiceof such procedures in general are known to those skilled in the art. Ofcourse, details may vary for any ceramic.

For example, a Mg-TTZ more finished ceramic body may be made by firing acorrespondingly larger machined green body in an oven at about from onethousand six hundred to one thousand nine hundred degrees C., preferablyabout from one thousand seven hundred to one thousand eight hundreddegrees C., for about from one to four hours, say, about from two tothree hours, with ramping temperatures leading to the firing temperatureincreasing from room temperature to the firing temperature at a suitablerate, say, about from one to two degrees C. per minute. After suchfiring, annealing is desirably carried out by gradually cooling the bodyfrom the firing temperature, keeping it in a heated condition, forexample, by gradually reducing the temperature of the hot, fired bodyabout from two hundred to five hundred degrees C., say, about threehundred fifty degrees C., below the firing temperature of the body, andholding the body at the annealing temperature for about from one tothree hours, say, about two hours. Cooling from the annealingtemperature may be carried out at any suitable rate, say, at a ratesimilar to, but the reverse of, the ramping rate, until the annealedceramic body is about room temperature. Such generally provides the morefinished Mg-TTZ ceramic body, which typically has a density whichapproaches or attains theoretical density. Advantageously thus, nofurther heat processing such as by HIP action on the fired and annealedMg-TTZ ceramic body is typically required.

A Y-TZP more finished ceramic body may be made by firing thecorrespondingly larger machined green body in an oven about from onethousand three hundred to one thousand five hundred degrees C. for abody made from micropowder, or about one thousand one hundred to onethousand three hundred degrees C. for a body made from nanopowder.Ramping, annealing and cooling procedures can be, in general terms,analogous to those for the Mg-TTZ ceramic. However, cooling at aboutfrom seven to ten degrees C. per minute, down to heat treatingtemperature, may be advantageously employed. Finally, HIP action underArgon or Nitrogen, say, Argon, at about from one thousand to threethousand pounds per square inch (psi) pressure, at a temperature aboutfrom one thousand to two thousand degrees C., for a cycle time aboutfrom four to twenty-four hours, with final cooling to room temperature.Thus, the finished ceramic body may be relieved of inorganic and organicsubstances, and approach or attain theoretical density.

Appropriate kiln furniture can be employed. Such furniture isbeneficially placed in non-critical parts of the body. For example, thefemoral knee joint implant component may be placed upside down in thekiln on kiln furniture that touches portions of the prosthesis that forma bone-implant interface rather than being placed right side up to haveits articulating condylar surfaces touched during firing.

The finished ceramic parts and components can be dense materials.Generally, the finished ceramic should be at least about ninety percentof theoretical density, or it may be at least about ninety-five,ninety-six, ninety-seven, ninety-eight, or ninety-nine percent oftheoretical density. Desirably, the density of the finished ceramicapproaches, and especially attains, theoretical density.

The more finished ceramic knee body may be further processed as desiredor required. Typically, any further processing is of a minor nature,particularly when compared to what would otherwise be required toprovide the final shape from machining a fired ceramic block. Thus,polishing and/or minor amounts of grinding are typically some of theonly mechanical finishing operation(s) carried out on the more finishedceramic body. A tantalum-vapor deposition or a hydroxyapatite coatingmay be applied to bone-interfacing surfaces to engender ingrowth ofbone. Various finished ceramic bodies to include those intended forimplantation into human or animal subjects are cleaned and sterilized byknown methods.

Such practice may be consolidated for illustration of preferences withreference to FIGS. 2 and 20, as follows:

-   -   Step 1: Monoclinic powder 10 is added to rubber ball cavity mold        18.    -   Step 2: The filled mold 18 is placed in CIP press 19.    -   Step 3: The press 19 is activated to provide an initial green        body, for example, green block 520.    -   Step 4: The green block 520 is subject to bisquing if needed to        provide bisqued green block 521.    -   Step 5: The green block 521 (or 520 if bisquing is not carried        out) is machined, say, by CNC machine, to provide machined green        ceramic body 530.    -   Step 6: The machined green ceramic body 530 is placed on        suitable kiln furniture 38 in kiln 39.    -   Step 7: The kiln 39 is heated to fire the precursor ceramic body        530 to provide more finished ceramic body 540.    -   Step 8: The more finished ceramic body 540 may be processed        further, for example, by polishing an articulating or bearing        surface and/or by preparing for insertion such inserts as ultra        high molecular weight polyethylene (UHMWPE) bushings, liners or        other inserts as may be desired, and/or by sterilization, for        instance, if it is for implantation as a prosthesis, to provide        finally finished ceramic body 550.

Again, and with initial reference to FIG. 2 and its depicted alternatesub-procedure, the initial green body 520 of ceramic can be provided byany suitable method. Preferably, again, it is provided by using a CIP 19on a suitable powder 10 such as a micropowder and/or nanopowder in CIPrubber mold body 18. Compare, WO 2004/080340. Thus, potential defectsthat may be caused by unidirectional pressing can be avoided. Again, thebody 520 may be bisqued 521. Sometimes it is not. The initial green body520, 521, 521′ can be machined without embedding it in an embedding massto make machined green body 530. A wax “handle” may be employed, inwhich machining wax is employed on one portion of the initial green bodyakin to an adhesive, without embedding it in the wax. However, even thatmay be avoided. For instance, the machining may be conducted with theaid of a device 600 that does not provide contact of the initial greenbody with an attachable substance, for example, machining wax. Thus, amechanical grip such as a vise or chuck may be employed. As analternative, a vacuum chuck may be employed as the device 600 to securean initial green body 520/521 and so forth for machining. However, agreen ceramic body, and especially a bisqued body may be infiltrated orimpregnated with an adjuvant, for example, heated, liquid paraffin wax,which may be carried out by simple soaking in a vessel, to providebisqued, infiltrated body 521′. The infiltration can be carried out tosaturation. The body 521′ can be removed from the vessel and graspedwith a mechanical and/or vacuum chuck, and machined. Note, steps 4A, 4B,4C of FIG. 2. When selecting a vacuum chuck, considerations includematching surfaces of the chuck with a suitable surface of the workpiece,and the capability to provide sufficient vacuum. Thus, a machined greenceramic body can be efficiently made. It may be clean without thenecessity to remove other substances such as a wax. Should the body havebeen infiltrated with an adjuvant such as the paraffin wax, this isconveniently removed at oven temperatures during firing. Again, themachined green ceramic body may be fired the kiln 39 having kilnfurniture 38 and/or further processed to provide more finished ceramicbody 540/550. Note, FIG. 2. Thus, highly intricate detail can beprovided ceramic prosthetic devices, heretofore unavailable in the art,to include not only a MgO-stabilized TTZ zirconia, posterior stabilizedfemoral component to a human knee, but also raised waffle pattern bumpsfor more secure mounting and engagement with resected bone. See, FIGS.2-8. And so, other articles can likewise be made readily and reliably,for example, prosthetic and non-prosthetic items such as those depictedin FIGS. 9-69.

The finished ceramics can be strong, tough materials. The finishedceramic preferably embraces a surgical implant which has as a featurethereof, a smooth, articulating ceramic surface.

The finished ceramics may be light-transmissive. In turn, certainceramic knee implant components of the invention can provide for a morerapid setting of surgical cement by use of illumination, say, with bluelight, through such an implant to the cement that is in contact withboth the bone stock and the implant reverse. Thus, cure and surgicaltimes can be decreased, and a more stable bone to implant interface maybe provided.

The finished ceramic knee implant parts and components can be made to beof sizes which are the same as or similar to those of correspondingparts and components made of metal. In certain cases, they may be madeto be slightly larger as may be desired.

In light of the foregoing and with particular reference to FIGS. 2-8,the machined green ceramic body 530, and hence the more finished ceramicbody 540 and the finally finished ceramic body 550 can be embodied as afemoral component 100 to a posterior stabilized knee. As a finallyfinished product, the femoral component 100, of one piece of ceramic,for the posterior stabilized knee can include frame 101 with side walls102; top 103T; distal condylar flange 104, which may include recess104R; posterior flange 105; and anterior flange 106. Interiorly facingbone-ingrowth enhancing and/or cement adhering surface 109 such as aporous or roughened surface can face in proximal and deep directions,and can include bumps 109B. Polymethylmethacrylate or other surgicalcement can be advantageously employed. Ridges 109R may define andreinforce the frame 101 and flanges 104, 105, 106. Femoral condylarsurface 110 of generally convex geometry, and advantageously of constantradius of curvature in the saggital plane, especially posteriorly,generally includes inferior, medial condyle 111; inferior, lateralcondyle 112; posterior, medial condyle 113; posterior, lateral condyle114, and may be considered to include anterior, medial condyle 115, andanterior, lateral condyle 116. On a superficial side of the anteriorflange 106 can be provided trochlear surface 117, on which the naturalor an artificial patella, i.e., knee cap, may generally ride. Typicallythe condylar and trochlear surfaces 110-117 are smooth and highlypolished, for example, by use of diamond grit or dust. Intracondylarnotch 118 is formed. Added stabilization is provided by posterior stop135, which contacts a corresponding member upstanding from the tibialtray liner (not illustrated) as is well known in the art.

With particular reference to FIGS. 9-15, note the following:

FIG. 9 depicts a finally finished ceramic body 550 that is embodied as amodular femoral component 100M for a knee implant, which includesone-piece ceramic frame 101 with side walls 102; top 103T, which mayhave hole 103TH; distal condylar flange (not illustrated); posteriorflange 105; and anterior flange 106. Femoral condylar surface 110 ofgenerally convex geometry, again, advantageously of constant radius ofcurvature in the saggital plane, especially posteriorly, generallyincludes inferior, medial condyle 111; inferior, lateral condyle (notillustrated); posterior, medial condyle 113; posterior, lateral condyle(not illustrated); and may be considered to include anterior, medialcondyle 115; and anterior, lateral condyle (not illustrated). On asuperficial side of the anterior flange 106 can be provided a trochlearsurface, on which the natural or an artificial knee cap may generallyride. Intracondylar notch 118 is present. Added, modular stabilizationcan be provided by metal or ceramic (or other suitable material) femoralbone stock insertion stem 37, which may be affixed by employment ofscrew 39 and/or washer 37W. Alternatively, or in addition, metal orceramic (or other suitable material) posterior stabilization stop rod135 may be inserted into posterior stabilization stop rod receiving hole135H in the frame 101 so that the rod 135P traverses the notch 118.Compare, FIGS. 3-8.

FIGS. 10 and 11 depict a finally finished ceramic body 550 that isembodied as a one-piece unicompartmental knee spacer device 100U, whichincludes ceramic frame body 101; articular surfaces 110; anterior cusp140A; and posterior cusp 140P. Compare, U.S. Pat. No. 6,206,927.

FIGS. 12, 13 and 14 depict a finally finished ceramic body 550 embodiedas a two-piece unicompartmental joint aligning device 100UU, whichincludes lower ceramic frame body 101L, and upper ceramic frame body101U; lower articular surface 110L, intermediate sliding surfaces 110S,and upper articular surface 110U; first, lower lobe 141L and first,upper lobe 141U, which may be disposed anteriorly when implanted;second, lower lobe 142L and second, upper lobe 142U, which may bedisposed posteriorly when implanted; engaging post 143P; and engagingpost receiving trough 143T. Compare, U.S. patent application Ser. Nos.10/717,104 and 11/189,027.

FIG. 15 shows a ceramic temporal mandibular joint implant 100TM/550 witharticular surface 110TM. The implant 100TM is in a form of a cup formounting on a resected jaw.

FIGS. 16-19 show more or finally finished ceramic bodies 540/550embodied as industrial components. As examples, FIG. 16 shows ceramicjournal bearing 100J; FIG. 17 shows ceramic flow control apparatus 100F,including control housing 100FH, piping 100FP, and valving 100FV;control housing; FIG. 18 shows set of gears 100G; and FIG. 19 showspulleys 100P.

FIGS. 20-49 show additional embodiments of finally finished ceramicbodies 550 for ginglymous joint implants. FIGS. 20-33 include depictionsof parts or components for a rotational knee joint 1000 with naturalload transfer, which includes femoral component 100 and tibial component200; FIGS. 34, 35, 36 and 37 depict a provisional femoral componentand/or a drill jig for the femoral component 100 of a knee implant suchas in FIGS. 21-29 and so forth; and FIGS. 38-49 depict modular kneejoint implants, which include modularity of the type that the joint orimplant can be found implanted in a first configuration, and, while thejoint or implant remains implanted, it can be converted to a secondconfiguration. In consideration of these figures, the following isnoted:

The femoral component 100 can include femoral component frame 101 whichmay be of a one-piece ceramic construction. The frame 101 can includeside walls 102; front wall 103, which may have upper segment 103U, lowersegment 103L, and/or hole 103H that may be tapped to receive screw 36;and top 103T, which may have hole 103TH and may have supporting flange103F, which may accommodate inferiorly insertable intramedullary femoralspike 37, which spike 37 may be part of a boxlike module 30 thatincludes side walls 32, front wall 34 that may have upper portion 34Uand lower portion 34L, and top 33, which mate closely with the walls102, 103, 103U, 103L and the top 103T, and/or including hole 34H throughwhich the screw 36 may pass on its way to the hole 103H, or which spike37, say again, made of Cr—Co alloy, may be secured with metal washer37W, and has screw-receiving hole 38 threaded for receiving screw 39that also secures boxlike modular rotation device 350. The frame 101also can include distal condylar flange 104; posterior flange 105,anterior flange 106; femoral bone stock insertion stem 107, which may beseparately addable 107A to stem receptacle 107R and be secured by setscrew 107S; and wall hole 108 for integral rotation device 150. Femoralbone-loss augments 104A and 105A for use together, and 104AS and 105ASfor separate use, may be provided, for example, of ceramic or suitableother material such as titanium or carbon fiber, which may be coated bytantalum vapor deposition. Interiorly facing bone-ingrowth enhancingsurface 109 such as a porous or roughened surface can face in proximaland deep directions, which surface 109 may also be provided a ceramicframe 101 through coating by tantalum vapor deposition techniques, asare known in the art. Femoral condylar surface 110 of generally convexgeometry, and advantageously of constant radius of curvature in thesaggital plane especially posteriorly, generally includes inferior,medial condyle 111; inferior, lateral condyle 112; posterior, medialcondyle 113; posterior, lateral condyle 114, and may be considered toinclude anterior, medial condyle 115, and anterior, lateral condyle 116.As before, on a superficial side of the anterior flange 106 can beprovided trochlear surface 117, on which the natural or an artificialknee cap may generally ride. Intracondylar notch 118, or inferiorlyinsertable module housing 301 for insertion of a modular rotation device350 and/or the modular spike 30/37, may be formed. Again, the condylarand trochlear surfaces 110-117, as are articular surfaces in general,smooth and highly polished. Condyle-backing femoral spikes 127 may beprovided. Rotation devices 150 and 350 are provided.

The rotation device 150, which may be substantially ceramic butpreferably in general is metal such as Co—Cr alloy, may be embraced byUHMWPE box insert 150B, and includes rotation member 151 generally withrotation member hole 152; taper pin receptacle 153, advantageouslyformed with a Morse-taper-accommodating cup; and punch-pin hole 154.Axle 155, which may be secured by axle plug 155P, runs through the hole152 and may run through radial bushing 156, say, of UHMWPE, whichbushing has axle hole 157; insert shoulder 158, which fits snugly in thewall hole 108; and member-spacing shoulder 159. The rotation device 150has highly polished taper pin 160, which can include cylindrical shaft161; and may include extraction groove 162 to extract the pin 160 fromthe receptacle 153, say, with a prying tool during surgical implantationof the prosthesis 1000; extraction-restriction punch-pin locking groove163; and taper lock tip 164, which can be made with a Morse-taper to fixthe pin 160 in the cup 153. When the pin 160 is so fixed, it may be setby insertion and fit of an extraction-restriction and/orrotation-restriction punch-pin 165 through hole 154 and into groove 163.Threads 166 may be present, preferably in conjunction with Morse-taper164, as an alternative for fastening the modular taper pin 160.

The rotation device 350 is completely modular and inferiorly insertableinto the insertable modular housing 301, preferably adapted for suchwith its walls 102 having a Browne & Sharpe taper, say, with an about1.5 to 2.0 degree taper 2×, or similar housing such as provided by theboxlike module with the spike 37, as an embodiment of the addablecomponent 30, which beneficially is made of Co—Cr alloy, and can includeswingable, depending male type part in housing 31 with side walls 32,preferably with a restraining Browne & Sharpe taper 32× about 1.6 to 2.1degrees; optional top wall 33, which may have top hole 33TH; and frontwall 34. Holes 52 in the side walls 52 accommodate hinge pin (axle) 55.Pivot block (rotation member) 51 can have hole 52A, which continuesalong the direction of the holes 52; taper pin cup 53, which may besmooth walled, tapered, say, with a Morse-taper, and/or provided withthreads 56; and punch pin hole 54. The taper pin 61 is inserted in thecup 53, and may be secured through punch pin 65 and/or threads 66. Therotation device 350 may be made with a one-piece depending male typepart as by having components 51 and 61 of one, integral piece.

A ceramic femoral knee component 100 may have a strength against aposterior condyle when tested in accordance with United States Food andDrug Administration (FDA) protocol of at least about 1500 pounds (lbs.);at least about 2000 lbs., or at least about 2500 lbs. Note, FIG. 4, testarrow 105T, and Example 1.

Provisional or trial femoral component 100T and/or drill jig 100DJ forthe femoral component 100 may be made of ceramic according to thepractice of the present invention. Sizing components 1005 (“hinge”) andaugment provisional or trial components 100AT may be used with thecomponent 100T.

The tibial component 200 can include tibial component frame 201, whichcan have tibial tray 202; dovetail liner-insertion rails 203;liner-stopping ramp or rotation safety stop 204, and, central stop 204C,particularly if part of double-capture locking mechanism 204X; screwholes 205 through which can be inserted bone-fastening screws 206; stem207—which may be insertable inferiorly into receiving cup 207C that maybe threaded, by provision of separate stem 207Q that may be threadedalso; or which may be insertable superiorly, even after implantation ofthe component frame 201, through hole 207H that may be threaded, byprovision of the separate stem 207Q that has a superior screwing headwith superior threads—and which may have distal taper 207T, a number of,say, three, distal ribbed grooves 208 and/or a number, say, two,underside flanges 208F; and interiorly facing bone-ingrowth enhancingsurface 209. The tibial articular surface 210 is of concave geometry insuitable complimentarity to the convex geometry of the condylar surface110, and generally includes superior, medial articular surface 211 andsuperior, lateral articular surface 212 on medial lobe 213 and laterallobe 214, respectively. On the underside of each lobe may be dovetailgrooves 215 for sliding along any rails 203; lobe-spanning portion 216;notch 217 for locking in cooperation with the stop(s) 204, 204C; andinter-condylar notch 218 analogous to the notch 118. Ramp 219 may makefor an easier installment over the stop 204. Such features 200-219 maybe provided on a separable tibial tray liner 220 of suitable material,for example, UHMWPE. Rotation device receptacle 250 may be in a form ofan essentially cylindrical cup 251, which may have top shoulder recess252. Rotation device receptacle liner 260, for example, UHMWPE, may beinserted into the receptacle 250 and its cup 251 so as to itself receivethe taper pin 60, 160. The liner 260 can include taper pin accommodatingcup 261; shoulder 262, which can fit in the recess 252; a number of,say, two to four, inside, axially directed grooves 263 to permit exit ofentrained body fluids during extension and flexion of the implantedjoint 1000 and consequent up and down motion of the taper pin 60, 160,which fits quite closely although movable within the liner cup 261; andoutside axially directed fluid-escape feature 264, say, groove, orpossible hole, to permit escape of liquids and/or gasses duringinsertion of the liner 260 into the receptacle 250, between which thereis a close, essentially immovable-in-use fit. Shoulder bevel angles A9 aand A9 b may be, respectively, for example, ninety degrees and onehundred eighteen degrees.

Tibial block augments may be provided, for example, as full augment 200For partial augment 200P. As skilled artisans would appreciate, RHK fulltibial block augments 200A can only be used with RHK tibial base plates.The table, which follows, lists some augments available from Zimmer,Inc.

Tibial M/L × RHK Full NexGen Partial Size AP (mm) Augments Augments 1 58× 41 Size 1 Size 1 2 62 × 41 Size 2 Size 2 3 67 × 46 Size 3 Size 4 4 70× 46 Size 4 Size 4 5 74 × 50 Size 5 Size 6 6 77 × 50 Size 6 Size 6

Beneficially, the knee implant 1000 has natural load transfer. As such,in addition to noted articular motions, the knee may carry a substantialamount, say, about ninety percent or more or about ninety-five percentor more of the load through the condyles.

Compare, U.S. Pat. Nos. 5,766,257 and 6,629,999.

In FIGS. 50 and 51 are depicted a zirconia ceramic, for example, Mg-TTZceramic, cruciate-retaining femoral component implant 100CR/550. Otherceramics such as alumina, although not as preferred, may be employed.Note, as in FIGS. 2-8, the waffle bump pattern on the bone-interfacingside of the component. This can, as with the other implants having them,provide a grip for surgical cement in addition to any rough surface onthe bone-interfacing side of the component. Note, too, the ridges on thebone-interfacing side of the component, which, in addition to providingfor a better cement bond, also help strengthen the implant. The implant100CR includes smooth articular condyles 110 but has no box or otherstructure between the lateral and medial inferior and posteriorcondyles. Smooth, patella-tracking articular surface 117 is presentbetween the condyles, especially as found between the lateral and medialanterior condyles.

In FIG. 52 is depicted a ceramic, for instance, a zirconia ceramic, say,Mg-TTZ ceramic, unicompartmental femoral knee component implant100UK/550. Note as in FIGS. 2-8 and 38 the waffle bump pattern andridges. The implant 100UK also includes a smooth articular condyle 110.

In FIGS. 53 and 54 are depicted a ceramic, for instance, a zirconiaceramic, again, for an example, Mg-TTZ ceramic, patellofemoral jointimplant 100PF/550. It includes smooth articular surface 110 and smooth,patella-tracking articular surface 117. Note the interior ridges. Arough surface can be provided on the interior surfaces as well. Postsare provided on the bone-interfacing, interior surface in the anteriorinferior position for mounting in cement on resected femoral bone stock.

FIGS. 55-58 depict ceramic, for instance, a zirconia ceramic, vertebracap ensembles 100VC/550 for mounting between adjacent, facing vertebraeof the spine, which include smooth, spherical section articular surfaces110. These may be implanted in the cervical, thoracic or lumbar regions,for example, in the thoracic region, say, between the ninth and tenthvertebrae essentially covering their vertebral bodies, in lieu of bonefusion when disc failure is presented. This may keep spinal flexibilityan option with disc failure. In one embodiment, the vertebra capensemble components are mounted through a cup device in thebone-interfacing surface of the cap over resected bone. In anotherembodiment, the components are mounted with the assistance of posts intoresected bone. Surgical cement may be employed. Of course, anothermaterial such as a suitable metal may be employed to make these vertebracap ensembles.

FIGS. 59-64 depict ceramic, for instance, a zirconia ceramic, forexample, Mg-TTZ ceramic, ankle joint ensemble having talus cap implant100AJ and tibial tray implant 200AJ (UHMWPE tray liner not illustrated).The talus cap 100AJ has articular surface 110 to articulate with naturaltissue in hemi-arthroplasty or with the tray liner in total jointreplacement arthroplasty, and is in a form of a cup for mounting over astump of resected bone as with the temporal mandibular joint 100TMJ(FIG. 15), the vertebra cap ensemble 100VC (FIGS. 55 and 56), and soforth and the like. The tibial tray implant 200AJ may be a suitablemetal or even ceramic, and includes an intramedullary spike and a cupfor receiving and retaining the liner having an articulating surface.

FIG. 65 depicts ceramic teeth in a ceramic body 530 in a precursorstage. These, for example, can be kiln treated to make finished ceramicbodies, say, of Mg-TTZ.

FIG. 66 depicts ice skate components 540/550, say, of Mg-TTZ.

FIGS. 67-69 depict ceramic intermediary articulation plate 202C, say, ofalumina or MG-TTZ, for a tibial tray 202, say, of titanium alloy, andsliding liner 220, say of UHMWPE. Employment of the plate 202C enhancesarticulation of the liner 220 riding on the plate 202C, say overarticulation otherwise between metal and UHMWPE. The plate 202C may bepress fit and/or cemented into the tray 202, which may havecircumferential lip 202L. Hole 202H may be provided through which can goa pin such as the pin 160 of a rotational knee femoral component into arotation device receptacle 250, which may have a liner, say, of UHMWPEor even ceramic. Rotation safety stops 204, 204C, 204X may be providedto keep the liner 220 from too far a rotation as it slides on theceramic plate 202C for which the liner is afforded accommodation as byprovision of suitable “cut out” volumes to interact with the stops 204,204C, 204X. Compare, FIGS. 28, 29, 31 and 32.

Numerous further embodiments can be effected in the practice of theinvention. Thus, for example, hand and foot digit joint implants can beprovided in ceramic hereby, and among these may be mentioned those ofthe fingers, thumb, and toes, notably, among the latter the great toe.Such an implant may have, for example, in the case of the great toe, asuitable metal tray and intramedullary spike with an attachable ceramictray liner having an articular surface, in lieu of the all-metalconstruction well known in the art.

The following examples further illustrate the invention.

Example 1

A finished body of a Mg-TTZ posterior stabilized femoral knee jointimplant component was begun through CIP action on an about 3-percentmagnesium oxide zirconia monoclinic 1-2 um micropowder with a binder,which was bisqued to provide a right angled 3½-inch×4-inch×4-inch block.Then CNC machining of the block provided a green machined body 121.95%of the size of the projected more finished ceramic, as a precursor to aposterior stabilized femoral knee component with standard sizedcondyles. The precursor was placed with its condyles up on fired Mg-TTZkiln furniture in an oven, which was ramped at an about 1˜2-degree C.per minute rate from room temperature to a firing temperature of some1725˜1775 degrees C. Firing was carried out for some 2˜3 hours. Then thetemperature was reduced at an about 5-degree C. per minute rate to anabout 1340-degree C. annealing temperature. Annealing was carried outfor an about 2-hour time. The annealed ceramic was cooled to roomtemperature at an about 5-degree C. per minute rate to make a morefinished posterior stabilized implant with great strength. See, FIGS.2-8.

The more finished ceramic knee femoral component can have its reverseside roughened up by grinding with a diamond bit. Its articulatingsurfaces can be polished with diamond dust. The ceramic knee implant canbe cleaned by immersion into an aqueous bath having a surfactant, withsonic agitation of the bath. Sterilization can be by radiation and/orethylene oxide.

A fired, finished ceramic posterior stabilized knee femoral component100 (FIGS. 2-8) made as above was designated as a demonstration model.In a demonstration, the component 100 was deliberately thrown across aroom onto a hard floor to impact against a wall. The audience cringedfor they had seen another ceramic knee implant shatter upon being merelydropped onto the floor, but they were awed as the demonstrationcomponent 100 remained intact.

Fired, finished ceramic posterior stabilized knee femoral components 100(FIGS. 2-8) made as above were tested by placing them separately in ajig and then applying stress to a posterior flange 105 along thedirection of test arrow 105T (FIG. 4) to correspond to the directionthat the FDA would require testing of a corresponding metal component. Afirst ceramic component with an about 1.7-mm thickness for the walls/top102/103 did not break when an about 1000-pound force was applied, and sothe component was subjected to 15-Hz fatigue stress for 200,000 cycleswith a 650-pound to 550-pound and 650-pound to 750-pound cycle withoutbreaking. The component was broken with an about 2250-pound load,failing about its box (a wall 102 and top 103), but not the condyleflange 105. A second component with an about 1.7-mm thickness for thewalls 102 was broken with an about 2300-pound load, again failing aboutits wall 102 and top 103 box, but not the condyle flange 105. This isgenerally about three times the minimum FDA value for Co—Cr.

A wall/top 102/103 of about 2˜3 mm thickness is desired.

Finite element analysis for the Mg-TTZ knee (FIGS. 2-8) with a 3-mmwall/top 102/103 thickness was carried out for stress along the arrow105T (FIG. 4). After 88,000,000 cycles the estimated strength was a2800-pound value.

Example 2

A block for a machined green body of for a Y-TZP posterior stabilizedfemoral knee joint component was made through pressure upon a monoclinicnanopowder, without binder. The block can be CNC-machined to provide amachined green ceramic body, fired and annealed, and further processedwith a 1200-degree C., 20,000-psi pressure HIP to provide atheoretically dense, posterior stabilized component.

Example 3

Mg-TTZ ceramic posterior stabilized knee femoral components 100 weremade by the method of Example 1 but with infiltration of a bisqued greenbody with paraffin wax as adjuvant, removing the infiltrated body, andthen machining the removed, infiltrated, bisqued green body. See, e.g.,FIGS. 2-8.

Example 4

Further ceramic products can be made by the foregoing methods. See,e.g., FIGS. 9-69.

CONCLUSION

The present invention is thus provided. Various features, parts, steps,subcombinations and combinations may be employed with or withoutreference to other features, parts, steps, subcombinations orcombinations in its practice, and numerous adaptations and modificationscan be effected within its spirit, the literal claim scope of which isparticularly pointed out as follows:

What is claimed is:
 1. A method for making a ceramic body prostheticimplant or prosthetic implant component of Mg-TTZ ceramic, which methodcomprises providing a bisqued initial green body of ceramic by providinga powdered ceramic material, which substantially is a monocliniczirconia having magnesium oxide for a stabilizer, and, without employinga binder additional to the powdered ceramic to do so: compressing thematerial in its powder form through a cold isostatic press operation toform a raw, pressed initial green body, and then heating the raw,pressed initial green body to a bisque stage to provide the bisquedinitial green body; and, after the foregoing steps are carried outwithout the employing a binder additional to the powdered ceramicmaterial, carrying out the following further steps: without embeddingthe bisqued initial green body of ceramic in an embedding mass,machining the bisqued initial green body to provide a machined, bisquedgreen ceramic body such that the machined, bisqued green ceramic bodyhas a shape, which is a precursor shape essentially analogous to, beingof the same proportions as, the shape of, but larger than, the ceramicportion of a fired predetermined finished ceramic body prostheticimplant or prosthetic implant component; and then firing the machined,bisqued green ceramic body to provide a fired Mg-TTZ ceramic bodyproduct, which is the same size and shape or essentially the same sizeand shape as the ceramic portion of the fired predetermined finishedceramic body prosthetic implant or prosthetic implant component; whereina hot isostatic press operation is not carried out.
 2. The method ofclaim 1, wherein the machined and fired ceramic body product has adensity of at least about 99 percent of theoretical.
 3. The method ofclaim 2, wherein the magnesium oxide is present at about from 3 to 3½percent by weight.
 4. The method of claim 2, wherein the heating to thebisque stage is carried out at about from 100 to 1100 degrees C.; thefiring is carried out at about from 1600 to 1900 degrees C. intemperature, with ramping leading to the firing carried out at aboutfrom ½ to 20 degrees C. per minute; and anealing is carried out bygradually cooling hot, fired Mg-TTZ ceramic body, which leads to thefired Mg-TTZ ceramic body product, from the firing temperature, keepingit in a heated condition, by gradually reducing the temperature of hot,fired Mg-TTZ ceramic body below the firing temperature and keeping itthere a suitable time, followed by further gradual cooling.
 5. Themethod of claim 1, wherein the bisqued green body of ceramic iscontacted by and infiltrated with an adjuvant, removed from any grossexternal adjuvant by which the bisqued green body of ceramic wascontacted for the infiltration; and the removed, infiltrated, bisquedgreen body of ceramic is machined.
 6. The method of claim 1, wherein thepowdered ceramic material has at most an about 10-um cross-section. 7.The method of claim 1, wherein polishing is the sole mechanicalfinishing operation to the fired ceramic body product.
 8. The method ofclaim 1, wherein the machined and fired ceramic body product is for orof a load-bearing intricate prosthetic implant or prosthetic implantcomponent.
 9. The method of claim 8, wherein the machined and firedceramic body product is for or of a femoral frame component for arotating knee joint implant.
 10. The method of claim 8, wherein themachined and fired ceramic body product is for or of a femoral componentfor a posterior stabilized knee joint implant.
 11. The method of claim8, wherein the machined and fired ceramic body product is for or of afemoral component for a cruciate-retaining knee joint implant, whichincludes medial and lateral condylar articular surfaces.
 12. The methodof claim 8, wherein the machined and fired ceramic body product is foror of a unicompartmental femoral condylar component for a knee joint.13. The method of claim 8, wherein the machined and fired ceramic bodyproduct is for or of an implant selected from the group consisting of aone-piece unicompartmental knee spacer device; a multi-pieceunicompartmental joint aligning device; a temporal mandibular joint capimplant; a patellofemoral joint implant; a vertebra cap; an ankle jointensemble or component; a bridge, a tooth or teeth; a tibial tray for aknee joint replacement implant; and an intermediary articulation platefor a tibial tray and liner for a knee joint replacement implant, orsaid plate assembed in combination with said tray.
 14. The method ofclaim 1, wherein the machined and fired ceramic body product has astrength corresponding to that which would be provided in a femoralcondylar component made of corresponding Mg-TTZ ceramic, which has astrength against a posterior condyle of said femoral condylar componentof at least about 1500 pounds (about 0.68 metric tons) when testedaccording to United States Food and Drug Administration standardscorresponding to standards for strength testing on a posterior condyleof a metal femoral knee component in which force is applied in aposterior to anterior direction on an unsupported portion of theposterior condyle.
 15. The method of claim 8, wherein the machined andfired ceramic body product has a strength corresponding to that whichwould be provided in a femoral condylar component made of correspondingMg-TTZ ceramic, which has a strength against a posterior condyle of saidfemoral condylar component of at least about 1500 pounds (about 0.68metric tons) when tested according to United States Food and DrugAdministration standards corresponding to standards for strength testingon a posterior condyle of a metal femoral knee component in which forceis applied in a posterior to anterior direction on an unsupportedportion of the posterior condyle.
 16. The method of claim 9, wherein themachined and fired ceramic body product has a strength against aposterior condyle of said femoral frame component of at least about 1500pounds (about 0.68 metric tons) when tested according to United StatesFood and Drug Administration standards corresponding to standards forstrength testing on a posterior condyle of a metal femoral kneecomponent in which force is applied in a posterior to anterior directionon an unsupported portion of the posterior condyle.
 17. The method ofclaim 10, wherein the machined and fired ceramic body product has astrength against a posterior condyle of said femoral component of atleast about 1500 pounds (about 0.68 metric tons) when tested accordingto United States Food and Drug Administration standards corresponding tostandards for strength testing on a posterior condyle of a metal femoralknee component in which force is applied in a posterior to anteriordirection on an unsupported portion of the posterior condyle.
 18. Themethod of claim 11, wherein the machined and fired ceramic body producthas a strength against a posterior condyle of said femoral component ofat least about 1500 pounds (about 0.68 metric tons) when testedaccording to United States Food and Drug Administration standardscorresponding to standards for strength testing on a posterior condyleof a metal femoral knee component in which force is applied in aposterior to anterior direction on an unsupported portion of theposterior condyle.
 19. The method of claim 12, wherein the machined andfired ceramic body product has a strength against a posterior condyle ofsaid femoral component of at least about 1500 pounds (about 0.68 metrictons) when tested according to United States Food and DrugAdministration standards corresponding to standards for strength testingon a posterior condyle of a metal femoral knee component in which forceis applied in a posterior to anterior direction on an unsupportedportion of the posterior condyle.
 20. The method of claim 13, whereinthe machined and fired ceramic body product has a strength correspondingto that which would be provided in a femoral condylar component made ofcorresponding Mg-TTZ ceramic, which has a strength against a posteriorcondyle of said femoral condylar component of at least about 1500 pounds(about 0.68 metric tons) when tested according to United States Food andDrug Administration standards corresponding to standards for strengthtesting on a posterior condyle of a metal femoral knee component inwhich force is applied in a posterior to anterior direction on anunsupported portion of the posterior condyle.
 21. The method of claim 1,wherein the machined and fired ceramic body product islight-transmissive so as to provide for rapid setting of surgical cementby use of illumination passed therethrough.